An Rh-negative unsensitized woman at 30 weeks presents with an episode of antepartum hemorrhage. After confirmation that the fetus is Rh-positive, what is the appropriate management regarding anti-D immunoglobulin?

• A No anti-D is required before 34 weeks of gestation
• B Anti-D 300 micrograms intramuscularly within 72 hours of the bleeding episode ✓
• C Anti-D 50 micrograms intramuscularly weekly until delivery
• D Intrauterine transfusion if the Kleihauer test is positive

Explanation

Any significant antepartum hemorrhage in an unsensitized Rh-negative woman with an Rh-positive fetus warrants anti-D immunoglobulin, conventionally 300 micrograms (approximately 1500 IU) given intramuscularly within 72 hours of the episode, followed by a Kleihauer-Betke test to detect larger fetomaternal bleeds needing extra doses. Anti-D is required throughout the third trimester, not just after 34 weeks, and intrauterine transfusion is reserved for severe fetal anemia, not routine prophylaxis.

Reference: Williams Obstetrics, 26th ed.

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Written and medically reviewed by the StethoPrep medical team.